Contact lens package

ABSTRACT

This invention provides a disposable contact lens package comprising a base having a top surface and a recessed well having a perimeter in the top surface, said well for holding said contact lens therein, said top surface comprising a raised seal volume surrounding said perimeter of said recessed well said raised surface having a cross-sectional shape comprising two linear sides that intersect the horizontal plane at angles alpha and beta, respectively, wherein angles alpha and beta independently have values from 125 to 170 degrees; and wherein said package further comprises a removable lidstock sealed to said raised seal volume.

FIELD OF THE INVENTION

[0001] The present invention relates to contact lens packages, and inparticular to disposable contact lens packages commonly referred to asblister packages.

BACKGROUND OF THE INVENTION

[0002] Soft hydrogel contact lenses have been increasing in popularityever since they were first introduced in the 1970's. Such contact lensesare conventionally packaged in the hydrated state and in a storagesolution. Currently, many contact lenses are packaged, along with theaqueous storage solution, in a disposable plastic blister package.Examples of blister packages can be seen in U.S. Pat. Nos. 4,691,820;5,524,419; 5,578,331, 5,649,410 and 5,722,536, the entire disclosures ofwhich are incorporated herein by reference. The base of a blisterpackage can either be part of the original contact lens mold or aseparately molded base. Examples of packages using the mold as part ofthe package can be seen in U.S. Pat. Nos. 5,036,971; 5,143,660;5,407,062 and 5,573,108, the entire disclosures of which areincorporated herein by reference. In all of the above mentioned packagetypes, the base that contains the contact lens and any aqueous storagesolution, whether it is a separated molded base or part of the originalcontact lens mold, is sealed by a flexible lidstock. This lidstock istypically a laminated foil which can be pulled back by a user to accessthe lens contained in the base. Typically, this lidstock is sealed tothe area surrounding the portion of the base containing the contactlens. This sealing area of the base has typically been a flat surfacearea, or a raised flattened annular surface as seen, for example, inU.S. Pat. No. 5,722,536. However, it has been found that this flatsurface, whether raised or not, can pose problems during the sealingprocess. If a molding process is used to form the blister package, forexample, the material may have some shrinkage, resulting in somewhatconcave sealing surface. Any low spots or unevenness of the sealingsurface can additionally cause microbubbles and result in a poor seal.Storage solution used to keep the contact lens hydrated caninadvertently spill and then remain on the sealing area; this can leadto a poor seal between the lidstock and the package base.

[0003] U.S. Pat. No. 6,082,533 attempted to address the just-describedproblem by providing a heat-sealing area consisting of a raised annulararea having an arcuate surface on the top of the raised area. Thatinvention only partially addresses the problem of storage solutionsplashing onto the heat-seal area of the package. For the design shownin FIG. 3 of that patent, the wall 220 that defines one side of theraised heat-seal area meets the surface of the flange at a 90 angle.This may cause problems when a lidstock is heat-sealed to the packageafter storage solution has been spilled on the package, because when theplastic begins to flow during heat-seal it can trap the solution betweenthe wall 220 and the flowing plastic. The solution may become superheated and may blow holes in the plastic of the heat-seal or in thesealed joint between the melting plastic and the flexible lidstock.

[0004] Accordingly, it is an object of the present invention to providea package for contact lenses that includes an improved sealing area onthe base of contact lens package.

SUMMARY OF THE INVENTION

[0005] This invention provides an improved contact lens package thatcomprises a base and a recessed well within the base for containing acontact lens, wherein the base comprises a raised seal volume comprisingtwo linear sides that meet the upper surface of a horizontal plane at anangle from 125 to 165 degrees. A lidstock is removably sealed to thebase at this raised seal volume. This package is preferably a disposablepackage.

[0006] This invention provides the benefit that when the plastic withinthe raised seal volume begins to flow during the sealing process, thenthe linear sides of the raised seal volume will provide a means forremoving, or pushing away any solution that was splashed onto the topsurface of the package including the raised seal volume. Further, thisinvention prevents that solution from getting trapped within, or underthe flowing plastic of the seal volume when a lidstock is heat sealed tothe base at the seal volume, which as described above causes thesolution to superheat and explode channels within the heat seal plasticand/or within the interface bonding joint between the heat seal plasticand the flexible lidstock.

BRIEF DESCRIPTION OF THE DRAWING

[0007]FIG. 1 is a top perspective view of a contact lens package of thisinvention shown prior to heat-sealing lidstock onto the package;

[0008]FIG. 2 is an enlarged cross-sectional view of the sealing area ofthe package of FIG. 1, with an exploded view of the seal volume, takenalong the line 2-2 shown in FIG. 1;

[0009]FIG. 3 is a top perspective view of an alternative embodiment of acontact lens package of this invention shown prior to heat-sealinglidstock onto the package; and

[0010]FIG. 4 shows an enlarged cross-sectional view of the sealing areaof the package of FIG. 3, with an exploded view of the seal volume,taken along the line 4-4 shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0011]FIG. 1 shows a disposable plastic blister package used forpackaging a contact lens. More specifically, as seen in FIG. 1, package10 generally comprises support base 12 with recessed well area 14 forreceiving and holding a contact lens (not shown). Generally, the contactlens will be packaged along with an aqueous storage fluid, such asbuffered saline solution, in well area 14. Package 10 may be molded froma material such as polypropylene, polystyrene, or similar plastic. Base12 includes a flange 15 having a top surface 16. The flange 15 ispresent all around, that is surrounding, the well area 14. As shown, theflange further comprises a raised seal volume 20 encircling theperimeter 28, that is, following the contour, of well 14 in the topsurface 16. In use, a contact lens is deposited in well 14 with aquantity of aqueous storage fluid, lidstock is applied, so as to coverat least the raised seal volume 20 or substantially the entire topsurface 16, typically by heat-sealing the lidstock to the raised sealvolume 20, thereby hermetically sealing the contact lens in well 14 ofpackage 10. The shape of the package 10, the base 12, the well 14, andthe raised seal volume 20 can vary as long as the elements of the raisedseal volume claimed below are present in the package 20.

[0012]FIG. 2 shows an enlarged cross-section of a portion of the package10 of FIG. 1 along the line 2-2, shown in FIG. 1. The raised seal volume20 is shown comprising two linear sides, a first linear side 21, and asecond linear side 22, which meet at a point or rounded point 23 whichis the uppermost surface of the raised seal volume 20. The first linearside 21 is located closer to the well 14. The second linear side 22 islocated further from the well 14. The first linear side 21 meets thewell 14 at corner 27 which defines the perimeter 28. The corner may berounded or sharp as desired. Angle alpha shown at the base of linearside 21 is defined by the intersection of linear side 21 with thehorizontal plane P as shown. Typically horizontal plane P is parallel tothe opening of the well when the package is resting on a flat surface.Most packages provide supports 29 or other structures for this purpose.Angle alpha is preferably from 125 to 170 degrees, more preferably from135 to 165 degrees, and most preferably from 145 to 165 degrees, andeven more preferably from 155 to 165 degrees. The second linear side 22meets the top surface of the flange 16 at angle beta. However, if theflange 16 is not in the horizontal plane then angle beta is defined asthe angle formed at the intersection of linear side 22 and thehorizontal plane P. Angle beta is preferably from 125 to 170 degrees,more preferably from 135 to 165 degrees, and most preferably from 145 to165 degrees, and even more preferably from 155 to 165. Preferably, thelinear sides have respective lengths D, E from 0.10 mm to 0.65 mm, morepreferably from 0.14 mm to 0.45 mm, and most preferably from 0.18 mm to0.25 mm. The preferred overall width A of the raised seal volume 20 isfrom 1.16 mm to 2.30 mm, more preferably from 1.22 mm to 1.85 mm, andmost preferably from 1.34 mm to 1.56 mm. The preferred overall height Bof the raised seal volume 20 is from 0.1 mm to 0.3 mm, more preferablyfrom 0.12 mm to 0.24 mm, and most preferably from 0.14 mm to 0.16 mm.

[0013] It is preferred that linear sides 21 and 22 and angles alpha andbeta are mirror images of each other; however that is not required aslong as both linear sides are present as parts of the raised seal volume20, and as long as the angles are both within the ranges specified.Lengths D and E and angles alpha and beta can vary and be different fromone another, depending on location of raised seal volume 20 in relationto other features and considerations within the package.

[0014] As shown, in the preferred embodiments, the flange extends awayfrom the well past the seal volume as shown, but in alternativeembodiments, the outside edge of the flange may not extend beyond theseal volume.

[0015]FIGS. 3 and 4 show an alternative embodiment of the package ofthis invention. FIG. 3 is a perspective plan view of the package andFIG. 4 shows an enlarged cross-section of a portion of the package 10 ofFIG. 3 along the line 4-4. FIGS. 3 and 4 show a package having a raisedseal volume 20 that is located a distance C between the perimeter 28 ofthe well 14 and the surface of the raised seal volume 20 closest to thewell 14. Note that C may vary in a package design, because it is notrequired that the raised seal volume follow the perimeter of the wellexactly or even at all. Preferably C is from 0 and 6 mm, more preferablyfrom 1 to 5 mm and most preferably from 2 to 5 mm. Additionally, theraised seal volume 20 as shown in FIGS. 3 and 4 has a rounded topsurface 43 contiguous with and located between the linear sides 21 and22. The radius of the rounded surface 43 is preferably from 1.0 mm to10.0 mm, more preferably from 1.5 mm to 6.0 mm, and most preferably from2.0 mm to 5.0 mm. Further the width F of the rounded surface 43 ispreferably from 0.50 mm to 2.0 mm, more preferably from 0.50 mm to 1.5mm, and most preferably from 0.50 mm to 1.0 mm. The other features ofthis embodiment are as described for the earlier embodiment, namely, theangles, lengths of the linear sides, the width of the heat seal, and theheight of the seal volume.

[0016]FIGS. 3 and 4 shows the preferred embodiment, because the distanceC provides a space in which the melted plastic of the raised seal volumemay flow and not create a rough surface that would be adjacent to,extend above, or flow into the well that may damage a contact lens as itis removed from the recessed well. However it may be possible inaccordance with this invention, if the correct sealing conditions andmaterials are used, to locate the raised seal volume adjacent to thewell by providing a large length D of side 21.

[0017] Many other modifications and variations of the present inventionare possible to one skilled in the field in the field in light of theteachings herein. It is therefore understood that, within the scope ofthe claims, the present invention can be practiced other than as hereinspecifically described.

We claim:
 1. A disposable contact lens package comprising a base havinga top surface and a recessed well having a perimeter in the top surface,said well for holding said contact lens therein, said top surfacecomprising a raised seal volume surrounding said perimeter of saidrecessed well said raised surface having a cross-sectional shapecomprising two linear sides that intersect the horizontal plane atangles alpha and beta, respectively, wherein angles alpha and betaindependently have values from 125 to 170 degrees; and wherein saidpackage further comprises a removable lidstock sealed to said raisedseal volume.
 2. The contact lens package of claim 1, wherein the linearsides are independently from 0.1 mm to 0.65 mm in length.
 3. The contactlens package of claim 1, wherein the overall width of the raised sealvolume is from 1.16 mm to 2.3 mm.
 4. The contact lens package of claim1, wherein the distance of the raised seal volume from the perimeter ofthe well is from 0 to 6 mm.
 5. The contact lens package of claim 1,wherein the height of the raised seal volume from the flange of thepackage is from 0.1 mm to 0.3 mm.
 6. The contact lens package of claim1, wherein angles alpha and beta independently have values from 145 to165 degrees.
 7. The contact lens package of claim 1, wherein anglesalpha and beta independently have values from 155 to 165 degrees.
 8. Thecontact lens package of claim 1, wherein the distance of the raised sealvolume from the perimeter of the well is from 1 to 5 mm.
 9. The contactlens package of claim 6, wherein the distance of the raised seal volumefrom the perimeter of the well is from 1 to 5 mm.
 10. The contact lenspackage of claim 1, wherein the height of the raised seal volume fromthe flange of the package is from 0.12 mm to 0.24 mm.
 11. The contactlens package of claim 6, wherein the height of the raised seal volumefrom the flange of the package is from 0.12 mm to 0.24 mm.
 12. Thecontact lens package of claim 7, wherein the height of the raised sealvolume from the flange of the package is from 0.12 mm to 0.24 mm. 13.The contact lens package of claim 1, wherein the height of the raisedseal volume from the flange of the package is from 0.14 mm to 0.16 mm.14. The contact lens package of claim 6, wherein the height of theraised seal volume from the flange of the package is from 0.14 mm to0.16 mm.
 15. The contact lens package of claim 7, wherein the height ofthe raised seal volume from the flange of the package is from 0.14 mm to0.16 mm.
 16. The contact lens package of claim 15, wherein the linearsides are independently from 0.1 mm to 0.65 mm in length.
 17. Thecontact lens package of claim 15, wherein the overall width of theraised seal volume is from 1.16 mm to 2.3 mm.
 18. The contact lenspackage of claim 1 further comprising a rounded surface from said linearsides.
 19. The contact lens package of claim 18 wherein said radius ofsaid rounded surface is from 1 to 10 mm.
 20. The contact lens package ofclaim 17, further comprising a rounded surface between said linear sideswherein said radius of said rounded surface is from 1.5 to 6 mm.